1. Field of Disclosure
Embodiments of the disclosure relate generally to systems and methods for cooling a room, such as a data center, equipment room or wiring closet, and more specifically to systems and methods for controlling load dynamics in a pumped refrigerant cooling system that provides cooling to data centers and the like.
2. Discussion of Related Art
Equipment enclosures or racks for housing electronic equipment, such as data processing, networking and telecommunications equipment, have been used for many years. Such racks are often used to contain and to arrange the equipment in large equipment rooms and data centers. Over the years, a number of different standards have been developed to enable equipment manufacturers to design rack mountable equipment that can be mounted in standard racks manufactured by different manufacturers. A standard rack typically includes front mounting rails to which multiple units of electronic equipment, such as servers and CPUs, are mounted and stacked vertically within the rack. An exemplary industry-standard rack is approximately six to six-and-a-half feet high, by about twenty-four inches wide, and about forty inches deep, and is commonly referred to as a “nineteen inch” rack, as defined by the Electronics Industries Association's EIA-310-D standard.
Management systems have been developed to manage the power distribution and cooling systems of data centers containing racks. One such management system is known as the InfraStruXure™ (“ISX”) manager offered by American Power Conversion Corporation of West Kingston, R.I., the assignee of the present disclosure, which is particularly designed to control the operation of large data centers.
Heat produced by rack-mounted equipment can have adverse effects on the performance, reliability and useful life of the equipment components. In particular, rack-mounted equipment, housed within an enclosure, may be vulnerable to heat build-up and hot spots produced within the confines of the enclosure during operation. The amount of heat generated by a rack of equipment is dependent on the amount of electrical power drawn by equipment in the rack during operation. In addition, users of electronic equipment may add, remove, and rearrange rack-mounted components as their needs change and new needs develop.
Previously, in certain configurations, data centers have been cooled by a data center's cooling system with computer room air conditioner (“CRAC”) units that are typically hard piped, immobile units positioned around the periphery of the data center room. These CRAC units intake air from the fronts of the units and output cooler air upwardly toward the ceiling of the data center room. In other embodiments, the CRAC units intake air from near the ceiling of the data center room and discharge cooler air under a raised floor for delivery to the fronts of the equipment racks. In general, such CRAC units intake room temperature air (at about 72° F.) and discharge cold air (at about 55° F.), which is blown into the data center room and mixed with the room temperature air at or near the equipment racks.
In other embodiments, the CRAC units may be modular and scalable so that the units may be placed anywhere within the data center depending on the cooling requirements within the data center. Such cooling units are described in pending U.S. patent application Ser. No. 11/335,874, entitled COOLING SYSTEM AND METHOD, filed on Jan. 19, 2006.
The rack-mounted equipment typically cools itself by drawing air along a front side or air inlet side of a rack, drawing the air through its components, and subsequently exhausting the air from a rear or vent side of the rack. In a certain embodiment, air is drawn through the equipment racks from a “cold” aisle, which is typically located at the fronts of the equipment racks. The heated air is exhausted from the equipment racks to a “hot” or “warm” aisle, which is typically located at the backs of the equipment racks. A disadvantage of the CRAC-type air conditioning system is that cool air is mixed with the room temperature air, which is inefficient. Ideally, to make the system as efficient as possible, and to utilize as little energy and floor space as possible, the highest possible temperature air should be drawn into the CRAC units and the outlet air generated by the CRAC should be a few degrees below room temperature. In addition, air flow requirements can vary considerably as a result of different numbers and types of rack-mounted components and different configurations of racks and enclosures.
In other embodiments, in order to control the flow of air throughout the data center, and to optimize the air flow as described above, it may be desirable to contain and cool the air within the hot and cold aisles, and in particular, the hot aisle. Examples of such a hot aisle air containment system may be found in U.S. Pat. Nos. 6,859,366 and 7,046,514. Other examples of hot aisle containment systems are provided by American Power Conversion Corporation of West Kingston, R.I., the assignee of the present disclosure, under model nos. ACDC1014, ACDC1015, ACDC1018 and ACDC1019.
In hot aisle/cold aisle configurations (“HA/HC”) and in hot aisle containment system configurations (“HACS”), it may be desirable to employ a modular cooling unit. With such cooling units, it is desirable to adjust the cooling capacity of the cooling unit so that the cooling capacity matches the heat generated by the load. Current approaches do not provide any means to adjust the cooling capacity of the cooling unit.